Pressing apparatuses are known, such as DE 39 20 204 C2, which discloses a pressure shoe loaded by a loading apparatus acting on its center. The loading apparatus is designed as a pressure transducer in the form of a hydraulic piston-cylinder unit. With such a pressing apparatus, the width of the pressure gap is larger than when two rollers interact. The time during which the web is retained in the pressure gap is thus extended. This yields advantages, especially when smoothing a paper web.
The number of ways in which to influence the web-shaped material is small with conventional pressing apparatuses. Besides varying the roller temperature and speed of the web, only the loading force, and thus the pressure stress in the pressure gap, can be varied.